Brief Description: Drill Drain to Skin / Countersink Cap
Unfortunately, the only hole that was prepunched in the skin for the fuel drain was the large center hole. The flange of the fuel drain itself was already prepunched and countersunk so this was used as a guide to drill the skin once everything was centered and clamped in place. After drilling the fuel drain to the skin, I used my countersinking jig doubler plate to countersink the holes in the fuel cap flange. After doing a couple of holes this way I realized the flange was actually thick enough that no jig was necessary. The rest of the countersinking went much faster.